The present invention relates to a method for fabricating a locally reinforced metallic microfeature, in particular of micro-reflectors. The microfeature, for example of a reflector plate and/or of a recess (cut-out), is locally strengthened in order to avoid deformations in the reflector plate, and to achieve the necessary stability for the recesses in order to suspend the tilting-type elements.
A method using an organic photo-sensitive resist layer in the micrometer range for fabricating micro-reflectors having locally thicker layers is described in the publication xe2x80x9cTexas Instruments Digital Light Processing and MEMS: Timely Convergence for a Bright Future,xe2x80x9d L. J. Hornbeck, Micromachining and Microfabrication 95, Plenary Session Paper, Texas, U.S., 1995. This conventional method uses a complicated and cost-intensive process for masking the reflector surface with a silicon dioxide mask and subsequently subjecting the aluminum layers to a plasma etching.
The photolithography employed in the method of the present invention, with subsequent wet-chemical etching of the metal layers, is less complicated and more cost-effective from a technological standpoint. To fabricate the patterned sacrificial layer and the photo-sensitive resist layers required by the method, both positive as well as negative photo-sensitive resists can be used. When working with the positive photo-sensitive resist, the exposed regions are removed following irradiation and development.
Exemplary embodiments for fabricating locally reinforced features in the form of micro-reflectors in micro-reflector arrays, where the recesses (posts and hollow posts) supporting the micro-reflectors, support two contiguous micro-reflectors, are depicted in the drawings and elucidated in the following description.